The present invention relates to a method of controlling a cruise control system.
Vehicle cruise control controls typically are optimized for when the vehicle is driving substantially straight.
The present invention provides a cruise control that selectively employs a strategy beneficial during traversal of a curved road section.
Advantageously, in an example operation, cruise control according to the present invention includes a software program which processes a number of inputs including lateral acceleration, differential lateral acceleration, torque command, and vehicle performance constants. The value of lateral acceleration is obtained from a brake control computer of the vehicle, from a lateral acceleration sensor, or derived from steering angle and vehicle speed. The value of torque command is obtained from a torque control computer of the cruise control.
In operation of the program, the lateral acceleration is monitored to determine if it has exceeded one of two thresholds. The first threshold is a low lateral acceleration limit and the second threshold is a high lateral acceleration limit. When the lateral acceleration of the vehicle is below the low lateral acceleration limit, the program does not compensate the cruise control torque command. When the lateral acceleration of the vehicle exceeds the low lateral acceleration limit, the torque command is monitored. During this monitoring, if the lateral acceleration of the vehicle remains constant or decreases, the program does not compensate the torque command; however, if the lateral acceleration increases, the torque command is compensated by setting the torque command equal to a minimum torque command, thereby clamping the torque command to the minimum torque command value. When the lateral acceleration of the vehicle exceeds the high acceleration limit, the torque command is further compensated by subtracting a calculated torque offset from the minimum torque command value.
These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification.